org.apache.wicket.markup.repeater.Item.java Source code

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Here is the source code for org.apache.wicket.markup.repeater.Item.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.wicket.markup.repeater;

import java.io.Serializable;
import java.util.Comparator;

import org.apache.wicket.markup.html.list.ListItem;
import org.apache.wicket.model.IModel;

/**
 * Container that holds components in a RefreshingView. One Item represents one entire row of the
 * view. Users should add all containing components to the Item instead of the view, this is
 * accomplished by implementing refreshingView.populateItem(Item item).
 * 
 * @see RefreshingView
 * 
 * @author Igor Vaynberg (ivaynberg)
 * 
 * @param <T>
 *            Model object type
 */
public class Item<T> extends ListItem<T> {
    private static final long serialVersionUID = 1L;

    /**
     * Constructor
     * 
     * @param id
     *            component id
     * @param index
     *            relative index of this item in the pageable view
     * @param model
     *            model for this item
     */
    public Item(final String id, int index, final IModel<T> model) {
        super(id, index, model);
    }

    /**
     * Constructor
     * 
     * @param id
     *            component id
     * @param index
     *            relative index of this item in the pageable view
     */
    public Item(final String id, int index) {
        super(id, index);
    }

    /**
     * @return the primary key assigned to this item
     */
    public String getPrimaryKey() {
        return getId();
    }

    /**
     * Comparator that compares Items by their index property
     * 
     * @author Igor Vaynberg (ivaynberg)
     */
    public static class IndexComparator implements Comparator<Item<?>>, Serializable {
        private static final long serialVersionUID = 1L;
        private static final Comparator<Item<?>> instance = new IndexComparator();

        /**
         * @return static instance of the comparator
         */
        public static Comparator<Item<?>> getInstance() {
            return instance;
        }

        /**
         * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
         */
        @Override
        public int compare(Item<?> lhs, Item<?> rhs) {
            long diff = lhs.getIndex() - rhs.getIndex();
            return diff == 0 ? 0 : diff > 0 ? 1 : -1;
        }
    }
}